Cylinder Drain Coxs

[sbwhart]

I've seen quite a few different design of cylinder drain coxs, some are operated by rods and links from the cab, some are steam activated and others are automatic.

One of the guys at the club has automatic drain cox fitted to his loco to a design that was passed onto him from another member he desribed them as having balls that open when they need to:- when water is in the cylinder, they don't have springs. I've tried to puzzle out how they work, I've not been able to ? said member and get a drawing off him he's been absent for a couple of months, hopfully he's OK.

Pic os said coxs



Can any one shed some light on this.

[Stuart]

Stew

they are quite simple

they are like a clack valve in the horizontal plane the steam /cylinder is at the top of the tee  the difference is that the ball can fall of the seat when the pressure is up the ball seats with water it falls off

see CoC

[dsquire]

Stew

Could it be that they are the type of ball (maybe plastic) that would float if there was water but it no water would sit over the hole and the pressure would keep it down and sealed. Just an idea.

I don't know steam so just tossing that out for You.

Cheers   

Don

[sbwhart]

Stew

they are quite simple

they are like a clack valve in the horizontal plane the steam /cylinder is at the top of the tee  the difference is that the ball can fall of the seat when the pressure is up the ball seats with water it falls off

see CoC

Thats the one Stuart where does the ball seat on the vertical seat into the T or on the horizontal seat into the drain, is the seat flat or conned?, I take it the chamber wher the ball is located has a bit of clearance to allow the ball to drop.

Sorry to press you on this as i want to fit this type to my Simplex.

Stew

[Stuart]

the seat is on the right hand side , seals to outlet or drain, the seal is flat faced as in a clack, give the chamber a little room. the ball needs to be able to drop off the seat.


note these do not seal perfectly and weep a bit but it does give an a vintage look


the ones on the class 4 tank are steam operated with pressure controlled from the cab that steam line also goes to the oil atomiser they use a ptfe popet with the shirt formed with a centre drill to throw up a frill on the back


Stuart

[Bogstandard]

Stuart,

If you could make you pictures a little larger, it would help greatly. Yours stays at the size shown in the post and is almost impossible to see.

Something around 800x600 would be ideal.

Thanks

John

[Stuart]

okcoky

will do john  I was trying to keep the inbounds so to speak


well John my system seems to be stuck on that file size  I have uploaded it as an attachment so it may be dl and expanded

it may be a product of the OS i run as its an unreleased one for a Mac ( i do dev work for apple ) i will try and sort out the reason 

Stuart

[Bogstandard]

That's it Stuart, my oldish eyes can read it now.

Many thanks

John

[Steamer5]

Hi Stew,
 Check out a copy of the Model engineer June 15 2012, issue 4432. Terence Hollands series on Farlie Complex he has a great drawing given you expertise should have no problem making. There have been several over the years in M.E if this one is not to your liking I'll happily check thru my database for other references.

Cheers Kerrin

[jonesie]

sorry to be off topic stew but did you or are you  going to post on this site your simpson and shipson  build. i have the cylinder and piston build, coming along good so far. thanks jonesie

[Dan Rowe]

Stew,
Here is an article with drawings showing a steam operated type of drain cock.
http://modelengineeringwebsite.com/Drain_cocks.html

Dan

[sbwhart]

Stuart thanks for the information and larger drawing I understand it now and recon I could make some.

Thanks for the info Kerrin and Dan I was toying with the idea od doing the steam jobs, but I'm having to do far more to get this loco running than I planned so I'm going to go for the method with less work content.

Jonesie

Pleased to her you're making progress.

The Simpson and Shipton build is currently being serialsed in ME, and I don't want to piss the editor off, but if you have any ? please don't hesitate to ask.

I'll can post an abridged version her though.

Stew

[Stuart]

BTW Stew they are Cocks   as in bib cocks,  stop cocks   

[jonesie]

thanks stew, so far all is going good but if i have any questions i will give you a shout. thanks jonesie

[doubletop]

I'm glad you asked this Stew, I also need four for my Simplex. My loco is already plumbed up to steam operated cocks but one must have been ripped off at some point and four manual cocks fitted. I have some drawings for steam operated cocks that came with the loco and there is  Terrance Holland's version in ME and now Dan's version.

I'm interested to see how you go with the auto cocks, It looks like there's not much required to make them

Pete

[sbwhart]

Pete

The reason I know about these types of cocks     is a quite a few of the guys at the club run with them and are very happy with the performance. If I can get hold of the drawing from the absent member i'll pass it on.

Stew

[Dan Rowe]

Stew & Pete,
This link has a drawing of the type shown by Stuart and another type of steam operated cock.

http://www.chaski.org/homemachinist/viewtopic.php?f=8&t=86236&p=179074&hilit=drain+cocks#p179074

Dan

[mzt]

sorry to be off topic stew but did you or are you  going to post on this site your simpson and shipson  build. i have the cylinder and piston build, coming along good so far. thanks jonesie

Stew,
sorry for the off-topic answer, but...

jonesie, where are the pictures???
Marcello

[sbwhart]

Just drawn a drain cock up, don't know if it will work but worth a try.
 

 

Drawing attached

[Stuart]

Stew

That looks a lot better than my CoC , should be Ok might take a bit of fettling to get it working as you would like at least there is not a mess of pipes around like my class 4 1/16 od steam lines and 3 /32 drains and one from the piston valve chamber



Stuart

[Dan Rowe]

Stew,
I finally located a drawing of one of these in my library. The reference is Live Steam July/Aug 93 author William Van Brocklin.

It is basically the same only the body thread is 1/4-32 not ME and the cap is drilled and reamed for the outlet. That is a nice touch as it makes machining the seat simpler. Not having to machine the seat in a hole was worth looking this up for me.

The bit I am concerned about is you have a 4.7mm bore which I am assuming is a 3/16 end mill to machine the seat with a 5/32 SS ball. This only leaves 1/64 clearance for the ball in the valve. Not much room for the ball to drop off and any tiny bit of dirt will gum up the works.

The design in LS has a 1/8" ball for that size valve chamber.

Another point the article made is this type of drain cock should only be used for D slide valves not piston valves.

I can make a sketch if needed.

Dan
   

[sbwhart]

Thanks for the input Dan I thought about using a 1/8 ball so I think that is what I'll use instead of 5/32

Bit unsure what you mean about the seating in the cap 

Stew

[Stuart]

I believe what Dan is saying  the body is drilled and taped through end to end and the seat is a hex union faced off to form the seat  with the plug at the rear


make making the valve seat on the lathe and not down a hole

I misread you drawing and as Dan stated the body bore need to be larger the ball should be loose

found this on the net and it shows the type that Dan has mentioned

[Dan Rowe]

Stuart beat me to the punch, and yes that was what I was attempting to say.

Here is my sketch.

Dan

[sbwhart]

Got it 

That is a lot simpler, I'll revise the drawing tomorrow

Thanks all

Stew

[Alan Haisley]

While reading this:

Another point the article made is this type of drain cock should only be used for D slide valves not piston valves.

I got to wondering just why it would work with a D valve but not with piston valves. Assuming it's a matter of timing, could someone explain just what happens 


Alan

[Dan Rowe]

Alan,
They will work with piston valves. It was bad wording on my part.

The author actually said they were not recommended with piston valves. The way he said to use them was to crack the throttle and SLOWLY warm up the cylinders.

A heavy hand on the throttle and a lot of water flow will seat the valve. A D slide valve will lift off the seat to prevent hydro lock. A piston valve can not relive the pressure and that is the issue.

Dan

[sbwhart]

Ok revised the drawing I kind of liked the idea of the ball sitting on a teat when its in the open position, but by way of an experiment I'll also make the other kind to how how it works.

Thanks for your inmput Guys 

Drawing attached

Stew

[Stuart]

you will have the worlds largest repository of auto drain information at your finger tips very soon


Stuart

[doubletop]

Stuart

A few posts back something similar crossed my mind however "the worlds largest repository of auto drain information at your finger tips" is probably a bit more polite than my version

Behave Pete; too many Pinot's.  A very useful thread and Dan's link to Chaskis website leads to a whole lot more information.

Pete

[Dan Rowe]

Pete,
Yes the Chaskis website is a gold mine of large scale locomotive information. One of my favorite posters over there is Bill Shields. He is a steam engineer who builds 3/4" scale locos.

Here is the link to where he has a few useful drawings including of course another steam operated drain cock in the misc section.
http://www.mehrs.com/

Dan

[sbwhart]

Dan

Thats a real usful site with some very interesting drawings

Thanks for sharing

Stew

[doubletop]

You may recall Stew made 6 auto drain cocks and offered the two spares to a good home. Well they arrived in NZ today and it didn't take long to get them fitted.



Thanks a lot Stew the are great. Hopefully the weather will hold out for the weekend and I'll be able to try them on my first steaming and give you a report.

Pete

[doubletop]

I tried Stews automatic cocks but couldn't get them to be closed when I thought they should be closed or open when I thought they should be open. To be fair I didn't give them a fair chance as I had other things that needed attention. Time moved on a bit the weather was bad so I couldn't run so I thought I'd use the time make some steam operated drain cocks.



(flex hose is the compressor line fitted to the lubricator clack. I find that the easiest option when testing on air as with the regulator closed the boiler doesn't get pressurized)

They are based on the drawings on the link posted by Dan http://www.mehrs.com/cylinder_cocks.zip I liked the look of these but they didn't work for me either. They'd be open at the start but once closed they wouldn't open again. Even with the steam 'off' pushing the shuttles back with a 1/16" rod I could feel pressure behind them keeping them closed.  I tried all sorts in an attempt to work out why they wouldn't open again. Then it occurred to me tonight the the setup that came with the loco, of a simple steam valve in the cab, wouldn't work. Once pipework was pressurized there was no way to dump the pressure. That then explained why Terence Hollands valve in ME4433 was more complicated than I had thought necessary, his is the only drawing of an operating valve I've seen. It allows the pressure in the pipe to be vented. So that's the job for the weekend, make one.

I've also fitted Stew's two valves with two steam operated valves to do a comparison. I'll report back

Pete

[Stuart]

Pete

 the valves that Stew sent you do work I have some on a class 2 and they are fine


as to your steam operated ones

1 the stam lines are far to big I used 1/16 od pipe on the class 4 tank
2 you need a valve that when you shut off the steam it opens a port to atmosphere , not a screwdown one but a rotary one with two ports one to your steam supply and one to air with the outlet to the valves,

on the class 4 they are one the same line as the atomiser for the steam oil so when the steam is on the atomiser runs and the valves close and visa versa with the atomiser doing the pressure release

I uses a ptfe slug for the valve in the cock and used a center drill up the back end to form a skirt to make a lip seal

Stuart

[doubletop]

Stuart

Thanks for the post. I saw it this morning and have spent the day waiting to get home.

I'm not suggesting there is anything wrong with Stews auto cocks. circumstances meant I didn't have the chance to try them properly. The plan is to try them again this weekend. They are already fitted to the loco along with two steam operated cocks.

The steam lines are 5/32" or 4mm which is what I had available and was similar to the steam feed from the backhead. I had no other point of reference to determine whether that was correct or not, I had assumed what had been fitted originally was "right". The loco came with the steam feed pipe capped off, a screwdown valve and four individual manual drain cocks. I had assumed tat the steam drain cocks had got themselves ripped off at some point and what was fitted was a quick fix. I now believe the steam operated drain cocks never worked properly so were replaced.

Your point 2 is what had me thinking as soon as I read it, something based on a rotary reverser sometimes fitted to "wobbler' engines. I got home tonight, sketched it up and have most of it made. just the steam connections to be turned and silver soldered in the morning and we'll see if it works. Lets call it a prototype for now. The drain cocks themselves are to the drawings I linked to.

So thanks for the input it triggered some thoughts on an alternative option and hopefully it will do the job, we'll see how it goes .

Pete

[Stuart]

Pete

glad my post provoked some thought


often the seed  to sort out the problem produces a better end result that has been done before

check your PM I cannot post because of Copy write issues

Stuart

[doubletop]

With the input provided by Stuart's comments I set about making a  rotary valve for the steam drain cocks and had it installed ready for a try out by Saturday lunchtime.



I also installed Stew's auto drain cocks to try them side by side.



I can report that Stew's auto drain cocks work fine. They allowed the water in the cylinders to drain, ejected any excess on starting the loco and then shut off when running.

The rotary valve also worked fine controlling the opening and closing of the steam operated drain cocks as expected. The only problem I had was when the valve was in the position to open the drain cocks the two faces leaked steam slightly because the port from the boiler manifold, at boiler pressure, was closed off by the valve face forcing the faces apart.  When in the position to close the drain cocks the boiler pressure was acting down the length of the feed pipe to the drain cocks and the leak didn't occur for some reason. In all it wasn't bad but not perfect.

Sunday started as wet and windy so needing something to do I made a version of the valve Terence Holland had featured in ME



I'll get it fitted and give it a try at some point.

Pete

[sbwhart]

Good to know you're making progress Pete thanks for keeping us posted.

Stew

[Stuart]

Pete

glad my info sparked a fix


Stuart

[doubletop]

Stuart sent me some diagrams of similar rotary valves. those had O rings in the steam feed port. So trip to the local O ring vendor this morning and I had some 1/16" x 1/16" cross section O rings. A retrofit to the existing valve wasn't going to work the way I'd done the end stop on the Mk1, so a case of start again.

The Mk1 and Mk 2 versions



Installed



Yet to try it out its raining at the moment.

Pete

[steamer]

Nice set up Pete!   Viton rings?

Dave

[doubletop]

A bit of an update on this. I couldn't get the rotary valve to seat sufficiently in the end I went for the plunger type valve from ME article.



And mounted it vertically in the cab floor as its too long to go on the manifold where I had the rotary valve.



I also modified the drain cocks so they vent forward and not down or sideways. Down picks up a lot of rubbish from the track bed especially at ground level and sideways is a bit inconvenient for bystanders, especially on a raised track



In hindsight that decision proved itself to be a good one when starting off for the very first time the jet of water can shoot 10 feet ahead of the loco.

The decision to go with the steam operated drain cocks has also resolved a problem that I'm beginning to think was the cause of the state the loco was in when I took it over. The crossheads, bushes and pins were all seriously worn out. When I first ran the loco with the manual and automatic drain cocks it knocked to some extent. I'm guessing that as the original steam drain cocks had never worked the previous owner had replaced them with four individual manual drain cocks. They would have bee impossible to operate on the move so could only be opened when stopped and closed prior to driving off. That would never have got rid  of all the condensate water and hence the loco would have knocked. I'm guessing that auto cocks would have this problem to some degree as once the regulator is opened and pressure is applied they will close regardless of whether there is water still in the cylinders. Remotely (steam) operated drain cocks give the driver full control and they can be held open when pulling away ensuring all the water is ejected the cylinders come back up to temperature

This short bit of video with me opening the drain cocks (and blow the whistle) for the camera as I go by.

<a href="https://www.youtube.com/watch?v=aq8ePsbRBR4" target="_blank">http://www.youtube.com/watch?v=aq8ePsbRBR4</a>

Pete

[sbwhart]

Great Job 

Stew

[Allysnell]

Hi guys I am look g for plans for the plunger type valve pictures in this thread, I think I know how to construct it however if anyone has better pictures or even better, plans, then that would be awesome. Ally

[b.lindsey]

Hi Ally and welcome to the group. Please take the time and post an introduction in the "introduce yourself" section so that we can learn of your model engineering interests.

Bill

[Allysnell]

Hi Bill will do and thanks for letting me join.

[doubletop]

Its from Model Engineer

2004 issue 4433 Terence Holland   Fairlie Complex: A Beginner's Paradox   
"Makes the drain cock operating gear. The operating valve, steam and exhaust pipework, commercial fittings, superheat, reversing linkage"

Pete